The sensory receptors They are structures located in different regions of our body that respond to the constant stimuli that we receive from the environment that surrounds us, that is, the "data" with which our sensory system is loaded with information, which is connected to our brain..
Our ability to hear, taste, see, smell and touch depends on our sensory organs, which contain in their specialized receptor structures, which have the permanent task of communicating to our central nervous system everything that happens around us..
When we say that the receptors communicate with our brain, then we are saying that they transmit information in the form of nerve impulses and, therefore, that they are composed of specialized cells for this purpose, which we know as neurons..
Article index
The main sensory organs of our body are the tongue, eyes, ears, nose and skin. These are associated with neurons that are capable of perceiving the specific signals that reach these senses and that can be chemical, mechanical, thermal, light, etc..
In response to such signals, these neurons translate the information they receive into a "language" that the brain understands, that is, a nerve impulse. In this way, our brain understands what happens and "makes the decision" of how to act on it.
Depending on their structure, sensory receptors can be of three types: free nerve endings, encapsulated nerve endings or specialized receptor cells.
However, it is easier to classify them according to the stimulus to which they respond, that is: to light, to some chemical substances, to temperature, to mechanical forces or pressures, among others. Thus, the following types are known:
- Mechanoreceptors: that they are able to perceive stimuli of touch, pressure, vibration and stretching
- Thermoreceptors: that they are capable of perceiving changes in temperature
- Photoreceptors: able to perceive and respond to light and changes in its intensity
- Chemoreceptors: that respond to different types of chemicals around them
Each of the sensory organs of our body is equipped with a set of some of these receptors that is capable of perceiving and responding to a specific stimulus, as we will see below:
Our hearing organs are the ears and it is thanks to these that we can perceive the different sounds and their characteristics, such as the direction from which they come, the intensity or volume, the tone and the timbre, etc..
The human ear is divided into three regions: the outer ear, the middle ear, and the inner ear. Sound waves are conducted to the inner ear through the outer and middle regions.
When we listen, the vibration of the sound waves is captured by the outer ear and is transmitted to the middle ear in the form of mechanical vibrations, as these waves collide with the membrane of the eardrum, one of the parts of the middle ear..
The eardrum transmits the vibration to the inner ear thanks to a chain of three very small bones that are in the middle ear. The vibration then passes to the inner ear, which is a space filled with a special fluid called "perilymph.".
With the vibration, the perilymph moves and this triggers a series of movements that finally reach the site where the cells with the sensory receptors are..
In the inner ear there is a special organ called the “organ of Corti”, which is the one that has in its structure the receptor cells specialized in the perception of perilymph vibrations..
These cells are capable of converting the information they receive mechanically (from the vibration of a liquid) into a nerve impulse that is transmitted to the sensory neurons and that our brain can understand as a "sound".
The auditory receptors are, therefore, mechanoreceptors, since they detect and respond to mechanical stimuli such as the vibration of the perilymph.
The tongue is our main taste organ and is covered by thousands of taste buds that, in turn, contain chemoreceptor-type sensory receptors that allow us to perceive different flavors.
Through these receptors, also called taste cells, we can discriminate between flavors such as sweet, salty, acid, bitter and umami (tasty).
Their function is relatively simple, since they are in charge of perceiving the chemical molecules that are in the food we eat and of translating the information "contained" in these molecules into electrical impulses, which is what our brain "understands".
The organs responsible for the sense of sight are the eyes. Through our eyes we can know the shape and distribution of the environment that surrounds us, with its depth, its colors, its shapes and movements, the distance at which its elements are from us, among others..
This sense is very important and those who lose it or are born with defects in it, develop much more other senses such as touch and hearing, for example, to be able to better locate themselves in the physical space where they are..
The eye is one of the most complex organs in our body. It is made up of various structures, separated into different regions, each of which serves a specific purpose..
The visual receptors that “interpret” what we see and communicate it to the brain in the form of nerve impulses are found in cells called rods and rods, which belong to a portion of the eye known as the retina..
These cells are sensitive to light, which is the specific stimulus that they are capable of perceiving, which is why the receptors in the eye are then known as photoreceptors..
In a nutshell: cones tell the brain about colors and give details of what we see, while rods tell the brain if what we see is moving and how far it is from us.
The nose is the sensory organ through which we can perceive and identify smells in the environment that surrounds us. As with taste, the sensory receptors associated with the nose are chemoreceptors, from which we understand that their job is to detect the presence of chemical molecules in the air we inhale..
These sensory receptors are specialized olfactory neurons that have their terminal portions in the nasal cavity and that express, in their plasma membrane, different proteins capable of binding to chemical molecules contained in the air..
These cells are directly connected to our brain, so when we smell something, the binding of membrane proteins to a particle is immediately translated as an electrical impulse that is conducted to the central nervous system and interpreted as a smell..
The largest organ in our body is the skin, as it covers us all. Throughout our skin there are various touch receptors distributed by which our brain is aware that we "touch" something.
These receptors, which can be mechanoreceptors and thermoreceptors, are generally sensory neurons located under our skin, whose terminal portions are responsible for "feeling" tactile stimuli and communicating them to our brain..
Thanks to these receptors we are able to perceive the temperature of the objects that we touch or that we approach, and we can also feel the surfaces of the objects, determine their texture and shape with our hands, etc..
Yet No Comments